An unexpected ethyl transfer reaction between Et2Zn anddo(t-butyl)glyoxaldiimine (t-BuDAB).Studies of thepersistent [EtZn(t-BuDAB)] radical which is in equilibrium with its C-C coupled dimer

Abstract

Whereas p-Tol{2}Zn reacts with t-BuN@?CHCH@?N-t-Bu (t-BuDAB) to give a stable 11 complex [p-Tol{2}Zn(t-BuDAB)], Et{2}Zn gives EtZnN(Et)(t-Bu)CH@?CHN-(t-Bu) via intramolecular ethyl transfer in the unstable Et{2}Zn(t-BuDAB) complex. In solution the stable persistent organozinc radical EtZn(t-BuDAB), which is formed in trace amounts in the Et{2}Zn/t-BuDAB reaction, is in equilibrium with its stable C@?C coupled dimer [EtZn-t-BuN@?CH(t-BuN)CH]{2}. The dimer can be prepared in quantitative yield by the reaction of (EtZnCl){4} with K(t-BuDAB).